Hybrid material and process for producing the same

ABSTRACT

A hybrid material includes a layer containing an octahedral sheet comprising octahedra linked with each other to provide a sheet-like structure and a tetrahedral sheet comprising tetrahedra linked with each other to provide a sheet-like structure; and an organic portion bonded by covalent bond to an element located at the tetrahedral site of the tetrahedra constituting the layer; each of the octahedra having an element at the octahedral site thereof with a valence in the range of from 3.5 to 4.5 on average over the entire octahedral sheet, and each of the tetrahedra having an element at the tetrahedral site thereof with a valence in the range of from 4.5 to 5.5 on average over the entire tetrahedral sheet. A process for fabricating the hybrid material and a process for controlling the content of the organic and inorganic components of the hybrid material are also provided. Any type of organic component is allowed to be incorporated in the hybrid material.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hybrid material comprising an organicand an inorganic component, which is suitable for use in a specialmember requiring superior properties concerning heat-resistance,rigidity, resistance against solvents, and the like. The presentinvention also relates to a process for producing the same, and to amethod for controlling the quantity of the inorganic and the organiccomponents in the hybrid material.

2. Description of the Related Art

Hybrid materials comprising an inorganic component such as a claymineral in combination with an organic component such as polyamide havebeen heretofore proposed. Hybrid materials of this type are of highpractical value, because they exhibit both of the characteristicsinherent in the inorganic and the organic components.

More specifically, a hybrid material comprising a layered inorganicmaterial such as layered clay mineral and an organic material is used asa catalyst for polymerization, etc. (reference can be made to, forexample, JP-A-Sho51-109998, JP-A-Sho62-72723, JP-A-Sho62-64827,JP-A-Hei5-306370, and JP-A-Hei5-32406; the term "JP-A-" as referredherein signifies "an unexamined published Japanese patent application").In the methods proposed in the foregoing JP-A-Sho51-109998,JP-A-Sho62-72723, and JP-A-Sho62-64827, a layered clay mineral issubjected to ion-exchange treatment to obtain a layered clay mineralrendered organic by replacing the interlayer cation with an ion of anamino acid, etc. The ion-exchanged layered clay mineral thus obtained isused thereafter as a starting material for producing, for example, apolymerization catalyst, a composite, etc. The methods disclosed inJP-A-Hei5-306370 and JP-A-Hei5-32406 provide a polymerization catalyst,a composite, etc., in a manner similar to that disclosed above, exceptfor using a zirconium phosphate type layered substance in the place ofthe aforementioned layered clay mineral.

For instance, JP-A-Hei5-306370 proposes a process for producing a hybridmaterial comprising an organic material and an inorganic material asfollows.

An α- or a γ-zirconium phosphate is dispersed and suspended in water,and after adding 12-aminododecanoic acid therein, the resultingsuspension is stirred for a duration of from 2 to 6 hours. The resultingsuspension is allowed to stand still at room temperature for a durationof several days, and a zirconium phosphate 12-aminododecanoic acidderivative is obtained by filtration, rinsing, and drying the suspensionthereafter. The product thus obtained is mixed with ε-caprolactam andaminohexanoic acid, and is charged into a glass polymerization tube.After purging the gas inside the reaction tube with nitrogen,polymerization was effected by maintaining the tube at 100° C. for aduration of 90 minutes, then at 250° C. for 2 hours under atmosphericpressure, and finally at 250° C. for 5 hours under reduced pressure. Ahybrid material of zirconium phosphate and polyamide is obtained in thismanner.

However, a hybrid material of an organic material and an inorganicmaterial obtained heretofore still have problems yet to be solved. In alayered clay mineral with exchanged organic cations or a layeredzirconium phosphate with an exchanged organic derivative, the layeredinorganic material is bonded to an organic molecule by ionic bond.However, a substance formed by ionic bond readily undergoes an ionexchange reaction with an externally supplied ion. Accordingly, areadily exchangeable substance such as an amino acid, a diamine, and adicarboxylic acid has been excluded from the organic constituent of thehybrid material. More specifically, for example, if an organic compoundsuch as 6-amino-caproic acid, etc., which is capable of producing6-nylon similar to ε-caprolactam is used, 6-amino-caproic acid and thelike may be readily substituted for the previously bonded cation. Insuch a case, the material cannot be obtained as designed. Considering acase of a nylon produced by condensation of a diamine (NH--R--NH) with adicarboxylic acid (COOH--R--COOH), e.g., 6,6-nylon, diamine issubstituted for the previously bonded cation during the synthesis. Thissometimes hinders the progress of interlayer polymerization of nyloncompletely, or sometimes allows the reaction progress only partly togenerate a function of nylon in the interlayer. Thus, the composite thusobtained may result with little improvement in mechanicalcharacteristics concerning elastic modulus, strength, elongation, etc.,or in barrier function against gas permeation. Moreover, the resultingcomposite may suffer embrittlement.

Thus, it is difficult to obtain a hybrid material with the desiredeffect in case a polymer which uses an ionic substance during thesynthesis thereof is employed. Undesirable polymers include 4,6-nylon,6,6-nylon, 6,10-nylon, and 6,12-nylon, in which a synthesized nylon saltis subjected to polycondensation reaction, because ions previouslyintroduced to a layered inorganic material by ion exchanging can beeasily exchanged by an externally provided ion. Polyolefins such aspolypropylene are also unsuitable, because metallic salts and the likeare used for the polymerization catalyst. In this case, ion exchangeproceeds during mixing or heating for polymerization. This hinders theformation of a composite material comprising separate and dispersed unitlayers (layered structure).

Furthermore, in case of synthesizing a compound having a catalyticfunction by adding another inorganic ion, etc., to a layered inorganicmaterial already rendered organic, the desired compound cannot besynthesized from a hybrid material having an ionic bond because of theion exchange reaction. Exchange adsorption of an element or a moleculeoccurs depending on the difference of ionization tendency. Thus, whentwo types or more of organic ions were to be dispersed in the interlayerof an inorganic material, selective adsorption occurs to a certain typeof ion. It can be understood therefrom that it is impossible to controlthe quantity of the organic ions bonded to the polymer or the quantityratio of the organic and the inorganic materials bonded to the layer.

In case of rendering a layered inorganic material organic by an ionexchange treatment, a relatively large molecule must be intercalatedbetween the layers by forcing it against the bonding force of thelayers. If the layered inorganic material is a clay mineral, water canbe used to facilitate the intercalation by expanding therewith thespacing between the layers. The same mechanism is believed to work onother types of layered substances. However, because layered inorganicmaterials have interlayer hydrogen bonds at a higher density than a claymineral has, it is assumed rather difficult for the layered inorganicmaterials to incorporate a water molecule between the layers. Thus, ingeneral, a reaction for a long duration of time is required in case ofintroducing organic ions to a layered inorganic material completely.Furthermore, even if the reaction for rendering the inorganic materialorganic should proceed to such an extent as to attain an average basalspacing in a range of from 15 to 30 Å, even a few bondings betweenlayers may prevent the material from swelling by intercalating polymer.In such a case, the expected effects cannot be obtained.

To obtain a material having a novel function by controlling thealignment of the organic molecules therein, or to intensify the functionas a barrier for gas permeation by dispersing large lamella crystals,the layered inorganic material must be previously developed into coarseand perfect crystals by crystal growth. Concerning a case of growingcrystals of a clay mineral, for instance, a smectite group mineralreadily forms an intercalated compound, but it changes into a largevermiculite crystal which takes a long time for intercalation, and thento a mica mineral which rarely takes up other interlayer cations. Incase of other layered inorganic compounds such as zirconium phosphate,it is difficult to render the compounds organic because the compoundtends to adsorb less organic ions as the crystals grow large. Moreover,it becomes more difficult to polymerize the organic ions with increasingthe size of crystals. Accordingly, so long as the inorganic substance isrendered organic based on ion adsorption, it is found difficult tocontrol the size and the perfection of a crystal.

On the other hand, the dispersibility in the later step ofpolymerization can be increased by reducing the size of the crystals.However, there is a limit in controlling the crystal size. That is, incase of a naturally occurring mineral such as a clay mineral, the sizeand the like of the crystals depend on the raw material. It is difficultto obtain crystals with a smaller or specific size, if any, amongnaturally occurring minerals. In case of synthesizing artificially aclay mineral or other types of layered inorganic materials, it isnecessary to perform some crystallization by hydrothermal reaction or bygelation at room temperature followed by a treatment such as heating orhydrothermal reaction. Further crystallization treatment is necessaryafter simple gelation at room temperature is performed, because most ofthe products are obtained at amorphous states by the gelation. Thedesired material cannot be obtained unless crystallization reaction iseffected to a certain extent.

Referring to a schematically drawn structure given in FIG. 2, a layeredclay mineral in general comprises an octahedral sheet consisting of aplurality of octahedra bonded with each other and each containingaluminum or magnesium in the octahedral site, being 6-fold coordinatedwith oxygen or hydroxyl groups. A tetrahedral sheet consisting of SiO₄tetrahedra is bonded by plane to plane with the octahedral sheet toprovide a layered structure. In case of bonding an organic portiondirectly with the inorganic structural unit above, an --O--Si--C--R(where R represents an organic portion) bond must be incorporated byonce cutting the Si--O--Si bond of the tetrahedral sheet. Although thisis not impossible, lattice defects must be inevitably introduced intothe crystals.

Referring to the schematically drawn zirconium phosphate structure inFIG. 3, reversely to the case of a clay mineral, the apices of thetetrahedral sheet are pointed in the direction opposite to theoctahedral sheet. Exchangeable cations such as H⁺ are bonded to theapical oxygen. In a common zirconium phosphate, organic cations arebonded by ionic bonds at the cationic sites. In such a structure, an--Si--C--R bond as illustrated in FIG. 1 can be introduced bysubstituting carbon for the apical oxygen located at the outer side ofthe tetrahedral sheet without inducing any defects in the crystalstructure.

Organic derivatives of zirconium phosphates containing organic portion(R) directly bonded to an inorganic layer of this type are described in,for example, G. Alberti and U. Costautino, in Chap. 5 of IntercalationChemistry (Edited by M. S. Whittingham and A. J. Jacobson), AcademicPress (1982). However, no information is available on the syntheticprocess for obtaining a composite of the substance and the polymer, thecharacteristics of a composite, and the means for realizing the effectof the composite as a polymerization catalyst.

As described in the foregoing, hybrid materials having been proposed inthe prior arts comprise an organic material and an inorganic materialbonded with each other by an ionic bond. Accordingly, only limited typesof organic materials are usable for the composite. In particular,industrially useful 6,6-nylon and polyolefins cannot be used in a hybridmaterial. Furthermore, because large layered inorganic materials are notavailable, the control of gas permeability and the like is still limitedin case of using the hybrid materials known to the present.

In U.S. Pat. No. 4,298,723 is proposed a hybrid material comprising anorganic compound bonded by covalent bond with an inorganic compound. Thehybrid material disclosed therein comprises a layered structurecomprising an octahedral sheet consisting of octahedra bonded with eachother in a sheet-like manner and a tetrahedral sheet consisting oftetrahedra bonded with each other in a sheet-like structure, and anorganic compound bonded to the layered structure. The octahedracomprises oxygen arranged in a 6-fold coordination with respect to atetravalent element such as zirconium in the octahedral site, and thetetrahedra comprises oxygen arranged in a 4-fold coordination withrespect to a pentavalent element such as phosphorus located at thetetrahedral site. The organic compound is bonded by covalent bond to thetetrahedral metal of the layered structure.

The only organic compound which is included in the hybrid material ofthe aforementioned prior art is an acrylic acid. The composite is usedspecifically as an adsorbent to adsorb particular components from amedium, an additive (filler) for a polymer composition, or a solidlubricant, etc. However, the superior characteristics inherent in anorganic material, such as high tensile strength, are not still expectedbecause the composite has a basal spacing as short as 4.2 nm or evenless. Furthermore, the composite has poor formability.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a hybrid materialcomprising an organic component and an inorganic component, in which anytype of organic component is allowed to be incorporated without anyrestriction. Another object of the present invention is to provide aprocess for fabricating the same, and a process for controlling themechanical properties and the like of the composite by controlling thecontent of the organic and the inorganic components of the hybridmaterial.

According to a first aspect of the present invention, there is provideda hybrid material comprising:

a layer containing an octahedral sheet comprising octahedra linked witheach other to provide a sheet-like structure and a tetrahedral sheetcomprising tetrahedra linked with each other to provide a sheet-likestructure, said tetrahedral sheet being linked to said octahedral sheetby plane to plane; and

a first organic portion bonded by covalent bond to an element located atthe tetrahedral site of the tetrahedra,

each of said octahedra having an element at the octahedral site thereofwith a valence in the range of from 3.5 to 4.5 on average over theentire octahedral sheet, and each of said tetrahedra having an elementat the tetrahedral site thereof with a valence in the range of from 4.5to 5.5 on average over the entire tetrahedral sheet,

wherein the layer is a zirconium phosphate-type layer expressed byMe[XO₃.R]₂, where Me represents at least one element selected from thegroup consisting of titanium, zirconium, germanium, tin, lead, andcerium; X represents at least one selected from the group consisting ofphosphorus and arsenic; and R represents said first organic portion,said X being bonded by covalent bond to said R.

In the present invention, "an element at the tetrahedral (or octahedral)site" is sometimes referred to simply hereinafter as "the tetrahedral(octahedral) element". All these elements mean an element located at thebody center of the tetrahedral (octahedral) unit.

The "layer" as referred to in the present invention signifies a laminate(layered structure) comprising an octahedral sheet and a tetrahedralsheet, as exemplified in FIG. 1.

According to a second aspect of the present invention, there is provideda process for producing a hybrid material comprising the step of:

reacting a substance containing: an element which functions as anelement at the octahedral site of octahedra constituting an octahedralsheet; and other elements constituting the octahedral sheet except forthe element at the octahedral site, with a substance containing: anelement at the tetrahedral site of tetrahedra constituting a tetrahedralsheet; a first organic portion that is combined by covalent bond withthe element at the tetrahedral site; and other elements constituting thetetrahedral sheet except for the element at the tetrahedral site, insuch a manner that the resulting octahedral sheet has elements at theoctahedral sites thereof with an average valence in the range of from3.5 to 4.5 and that the resulting tetrahedral sheet has elements at thetetrahedral sites thereof with an average valence in the range of from4.5 to 5.5,

thereby obtaining a hybrid material having a layer containing theoctahedral sheet comprising octahedra linked with each other to providea sheet-like structure and the tetrahedral sheet comprising tetrahedralinked with each other to provide a sheet-like structure, saidtetrahedral sheet being linked to said octahedral sheet by plane toplane, and a first organic portion bonded by covalent bond to theelement located at the tetrahedral site of the tetrahedra.

The reaction step is performed by reacting a substance containing: atleast one element selected from the group consisting of titanium,zirconium, germanium, tin, lead, and cerium; and oxygen, with asubstance containing: at least one element selected from the groupconsisting of phosphorus and arsenic; the first organic portion bondedthereto; and oxygen, to obtain a zirconium phosphate-type layerexpressed by Me[XO₃.R]₂ for said layer, where Me represents at least oneelement selected from the group consisting of titanium, zirconium,germanium, tin, lead, and cerium; X represents at least one selectedfrom the group consisting of phosphorus and arsenic; and R representsthe first organic portion, said X being bonded by covalent bond to saidR.

According to a third aspect of the present invention, the processfurther comprises the step of controlling the content of an organiccomponent and an inorganic component in a hybrid material, whichcomprises:

controlling the content of an organic component and an inorganiccomponent in a hybrid material, by adding a substance containing theelement for the tetrahedral site but to which no organic portion isbonded to the substance containing the element for the tetrahedral siteat a predetermined quantity ratio and the organic portion bonded theretoby covalent bond.

Another controlling step may comprise:

controlling the content of an organic component and an inorganiccomponent in the hybrid material by controlling the gross number offunctional group of the first organic portion which is capable ofbonding with a second organic portion and bonding the second organicportion to the functional group of said first organic portion.

According to a fourth aspect of the present invention, there is provideda surface hardening material comprising:

a layer containing an octahedral sheet comprising octahedra linked witheach other to provide a sheet-like structure and a tetrahedral sheetcomprising tetrahedra linked with each other to provide a sheet-likestructure, said tetrahedral sheet being linked to said octahedral sheetby plane to plane; and

an organic portion bonded by covalent bond to an element located at thetetrahedral site of the tetrahedra;

said octahedral sheet comprising octahedra each having an element at theoctahedral site thereof with a valence in the range of from 3.5 to 4.5on average over the entire octahedral sheet, and said tetrahedral sheetcomprising tetrahedra each having an element at the tetrahedral sitethereof with a valence in the range of from 4.5 to 5.5 on average overthe entire tetrahedral sheet.

According to a fifth aspect of the present invention, there is provideda wrapping material comprising:

a layer containing an octahedral sheet comprising octahedra linked witheach other to provide a sheet-like structure and a tetrahedral sheetcomprising tetrahedra linked with each other to provide a sheet-likestructure, said tetrahedral sheet being linked to said octahedral sheetby plane to plane, and

an organic portion bonded by covalent bond to an element located at thetetrahedral site of the tetrahedra;

said octahedral sheet comprising octahedra each having an element at theoctahedral site thereof with a valence in the range of from 3.5 to 4.5on average over the entire octahedral sheet, and said tetrahedral sheetcomprising tetrahedra each having an element at the tetrahedral sitethereof with a valence in the range of from 4.5 to 5.5 on average overthe entire tetrahedral sheet.

According to a sixth aspect of the present invention, there is providedan ultraviolet radiation absorber comprising:

a layer containing an octahedral sheet comprising octahedra linked witheach other to provide a sheet-like structure and a tetrahedral sheetcomprising tetrahedra linked with each other to provide a sheet-likestructure, said tetrahedral sheet being linked to said octahedral sheetby plane to plane; and

an organic portion bonded by covalent bond to an element located at thetetrahedral site of the tetrahedra;

said octahedral sheet comprising octahedra each having titanium orcerium at the octahedral site thereof, and said tetrahedral sheetcomprising tetrahedra each having an element at the tetrahedral sitethereof with a valence in the range of from 4.5 to 5.5 on average overthe entire tetrahedral sheet.

According to a seventh aspect of the present invention, there isprovided an electron donor comprising:

a layer containing an octahedral sheet comprising octahedra linked witheach other to provide a sheet-like structure and a tetrahedral sheetcomprising tetrahedra linked with each other to provide a sheet-likestructure, said tetrahedral sheet being linked to said octahedral sheetby plane to plane; and

an aromatic organic group bonded by covalent bond to the element locatedat the tetrahedral site of the tetrahedra;

said octahedral sheet comprising octahedra each having an element at theoctahedral site thereof with a valence in the range of from 3.5 to 4.5on average over the entire octahedral sheet, said tetrahedral sheetcomprising tetrahedra each having an element at the tetrahedral sitethereof with a valence in the range of from 4.5 to 5.5 on average overthe entire tetrahedral sheet, and said layer being doped with transitionmetal ions,

wherein the electron donor is an anion polymerization initiator.

The hybrid material according to the present invention comprise anorganic portion bonded by covalent bond to the tetrahedral element ofthe tetrahedra constituting the tetrahedral sheet. Accordingly, there isno need of rendering the organic portion cationic as in the conventionalhybrid materials based on a clay mineral or zirconium phosphate. Thissignifies that any type of organic molecule can be bonded to theinorganic material, and that almost all of the organic molecules can beused to produce a hybrid material. Moreover, the present inventionallows the use of a polymer extensively used in the industry, whichutilizes an ionic substance in the synthetic stage thereof (forinstance, 4,6-nylon, 6,6-nylon, 6,10-nylon, 6,12-nylon, and othersobtained by effecting condensation polymerization after oncesynthesizing a nylon salt), or of a polyolefin such as polypropylene.Thus, the present invention enables designing a substance comprising anorganic portion bonded to the tetrahedral element of the tetrahedra fromthe synthetic step thereof.

Furthermore, the hybrid material according to the present invention canbe obtained in large crystals, because the organic portion is bonded bycovalent bond to the tetrahedral element. Thus, the mechanicalproperties and the gas permeability of the resulting composite can becontrolled.

The hybrid material according to the present invention allows the use ofa material selected from a wide variety of organic materials, such aspolyamides and polypropylene.

The gas permeability and the mechanical properties of the hybridmaterial according to the present invention can be controlled, becauselarger crystal sizes are achieved in the present hybrid material.

In the present invention, as the basal spacing of the layers becomesgreater, the hybrid material more readily exhibits properties inherentin the organic portion present between the layers. Accordingly, thebasal spacing preferably averages 4.4 nm or more. With the spacingfalling within this range, the organic portion present between thelayers would exhibit excellent tensile strength, moldability, and so onwithout being affected by the inorganic compound of the layer. Morepreferably, an average basal spacing is 5.0 nm or more.

Herein, an average basal spacing means the mean value of the spacingbetween the center of gravity of one layer and that of another one. Thevalue is available by mathematically averaging basal spacings, even iflayers are dispersed uniformly, or aggregated by contacting with eachother. This average basal spacing can be obtained by x-ray diffraction,as shown in the Examples. Specifically, as illustrated in FIG. 7, it canbe calculated by using x-ray diffraction peaks when 2θ is 10° or less,from the following Bragg's formula:

    λ=2d sin θ(λ: x-ray wavelength, d: spacing between the planes, θ: diffraction angle).

Why the hybrid material with the basal spacing of 4.4 nm or more, morepreferably 5.0 nm or more, can exhibit excellent tensile strength,moldability, and so on has not been clarified yet.

Following is just speculation to help understanding the result performedby the structure of the present invention. Presuming that layers havingan organic portion therebetween are arranged in parallel, the greaterthe number of the carbon atoms is, the longer the chain of the organicportion and the greater the basal spacing (spacing between the center ofgravities of the layers) is. Further, if the layers are zirconiumphosphate type layers, the thickness thereof is about 1.1 nm. If theorganic portion is linearly-chained hydrocarbon, an organic portioncomprising six carbon atoms as one unit has the length of about 1.1 nm.If 6,6-nylon is employed as an organic portion, the basal spacing shouldbe 3.3 nm wherein the distance from the center of gravity to the surfaceof the layer is about 0.55 nm, and the length of the organic portion isabout 2.2 nm for the nylon having two units of a hydrocarbon chain. Inthis case, the distance from the gravity center of a layer to the centerof the space between layers measures 1.65 nm. This is too short for theorganic portion to affect entire properties of the hybrid material.Since the inorganic component dominates the properties of the material,desirable properties inherent in the organic portion can not beexpected.

When another unit of the organic portion (constituted by six carbonatoms) is further added, the added organic portion will be sufficientlyfar from the layers to exhibit its properties without being affected bythe layers. In this case, the basal spacing becomes about 4.4 nm,because about 1.1 nm of a single unit is added to about 3.3 nm.

Furthermore, another half of a unit--about 0.6 nm, may be added to makelonger the length of the organic portion, thereby readily exhibitingproperties inherent in the organic portion. In this case, the basalspacing becomes 5.0 nm.

It should be, however, noted that as the organic portion becomes longerand the basal spacing becomes larger, the quantity of the layersthemselves becomes smaller. This detracts the properties such as heatresistance, gas barrier ability, and the like inherent in organiccompound of the layers. In view of that, the upper limit of an averagebasal spacing is preferably 100 nm.

As discussed hereinabove, the basal spacing can be made larger byincreasing molecular weight of the organic portion bonded by covalentbond with tetrahedral elements or the number of carbon atoms of linearlychained organic molecule.

The above and other objects, features and advantages of the presentinvention will become more apparent from the following description whentaken in conjunction with the accompanying drawings in which a preferredembodiment of the invention is shown by way of illustrative examples.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematically drawn structure of a hybrid material accordingto an embodiment of the present invention;

FIG. 2 is a schematically drawn structure of a clay mineral;

FIG. 3 is a schematically drawn structure of zirconium phosphate;

FIG. 4 is a diagram showing X-ray diffraction patterns of a hybridmaterial according to an embodiment of the present invention;

FIG. 5 is a diagram showing infrared (IR) absorption spectra for hybridmaterials according to an embodiment of the present invention;

FIG. 6 is a schematically drawn diagram showing the alignment of2-carboxylic acid on a layer surface of a composite according to anembodiment of the present invention;

FIG. 7 is a diagram showing X-ray diffraction patterns of hybridmaterials according to an embodiment of the present invention;

FIG. 8 is a diagram showing thermogravimetric (TG) curves of a hybridmaterial according to an embodiment of the present invention;

FIG. 9 is a diagram showing thermogravimetric (TG) curves of a hybridmaterial according to another embodiment of the present invention;

FIG. 10 is a diagram showing thermogravimetric (TG) curves of a hybridmaterial according to a still other embodiment of the present invention;

FIG. 11 is a diagram showing thermogravimetric (TG) curves of a hybridmaterial according to a yet other embodiment of the present invention;

FIG. 12 is a diagram showing X-ray diffraction patterns of a hybridmaterial according to an embodiment of the present invention;

FIG. 13 is a diagram showing X-ray diffraction patterns of a hybridmaterial according to another embodiment of the present invention;

FIG. 14 is a diagram showing X-ray diffraction patterns of a hybridmaterial according to a still other embodiment of the present invention;

FIG. 15 is a diagram showing X-ray diffraction patterns of a hybridmaterial according to a yet other embodiment of the present invention;

FIG. 16 is a diagram showing X-ray diffraction patterns of a hybridmaterial according to a further other embodiment of the presentinvention; and

FIG. 17 is a diagram showing infrared (IR) absorption spectra for hybridmaterials according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

A hybrid material according to a first aspect of the present inventioncomprises a layer containing an octahedral sheet comprising octahedralinked with each other to provide a sheet-like structure and atetrahedral sheet comprising tetrahedra linked with each other toprovide a sheet-like structure, and an organic portion bonded bycovalent bond to an element located at the tetrahedral site of thetetrahedra constituting the layer, provided that the octahedral sheetcomprises octahedra each having an element at the octahedral sitethereof with a valence in a range of from 3.5 to 4.5 on the average overthe entire octahedral sheet, and that the tetrahedral sheet comprisestetrahedra each having an element at the tetrahedral site thereof with avalence in a range of from 4.5 to 5.5 on the average over the entiretetrahedral sheet.

The hybrid material according to the present invention comprises anoctahedral sheet having an average valence in a range of from 3.5 to 4.5for the octahedral element of the octahedra over the entire octahedralsheet, and a tetrahedral sheet having an average valence in a range offrom 4.5 to 5.5 for the tetrahedral element of the tetrahedra over theentire tetrahedral sheet. Accordingly, an organic portion can be bondedby covalent bond to the element at the tetrahedral site of thetetrahedra constituting the tetrahedral sheet.

More specifically, referring to the schematically drawn structure inFIG. 1, an organic portion can be bonded to the element at thetetrahedral site of a tetrahedron by covalent bond in case the basalplane of the tetrahedron is bonded to the side planes of the octahedron,and the apex is located on the outer side of the tetrahedron (i.e., inthe layer, on the side opposite to the octahedral sheet). In thismanner, carbon atom of the organic portion can be shared at the apicesof the tetrahedra to form a covalence bond between the organic portionsand the elements located at the tetrahedral sites of the tetrahedra.

For instance, in case the tetrahedral elements of the tetrahedraconstituting the tetrahedral sheet have an average valence of 5, amonovalent electron can be supplied from the element at the apex locatedon the outer side of a tetrahedron to form a covalent bond, and the restof the apical elements (three elements) each supply a 4/3-valentelectron. Each of the three apical elements remain with a valence of 2/3(2-4/3=2/3). Thus, six anions each having a valence of 2/3 surround theelement located at the octahedral site of the octahedron. To cancel outthe negative valence of the six anions, the octahedral element of theoctahedra must have an average valence of 4 on average over the entireoctahedral sheet. The average valence of the octahedral element and thatof the tetrahedral element may fluctuate around 4 and 5, respectively.More specifically, the average valence of the octahedral element can bea value in a range of from 3.5 to 4.5, and the average valence of thetetrahedral element can be a value of from 4.5 to 5.5. In case of anoctahedral sheet, the deviation of the valence of 4.0 for the octahedralelement can be compensated by deviating the valence of the tetrahedralelement in such a manner that the charge of the layer as a whole may beneutral. Otherwise, an interlayer cation corresponding to the chargedeviation can be introduced to neutralize the charge of the entirestructure.

The element located at the octahedral site of the octahedra constitutingthe octahedral sheet must have an average valence in a range of from 3.5to 4.5 over the entire sheet. Specific examples of the octahedralelement include a Group IVa element of the periodic table such astitanium (Ti), zirconium (Zr), and hafnium (Hf); a Group VIb elementsuch as silicon (Si), germanium (Ge), tin (Sn), and lead (Pb); or anelement belonging to other groups but which is capable of taking atetravalent state, such as cerium (Ce). For the octahedral site, notonly a single element, but also two or more elements can be employed.

The element located at the tetrahedral site of the tetrahedraconstituting the tetrahedral sheet must have an average valence in arange of from 4.5 to 5.5 over the entire sheet. Specific examples of thetetrahedral elements include an element capable of taking a pentavalentstate, such as a Group Vb element of the periodic table such asphosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi); or aGroup Va element such as vanadium (V), niobium (Nb), and tantalum (Ta).For the tetrahedral site, not only a single element, but also two ormore elements can be employed.

Furthermore, the tetravalent element of the octahedral site may bereplaced by yttrium (Y) and niobium (Nb), or the pentavalent element ofthe tetrahedral site may be replaced by Si or sulfur (S), so long as theoctahedral elements in the octahedral sheet as a whole maintain anaverage valence in a range of from 3.5 to 4.5 and the tetrahedralelements in the tetrahedral sheet as a whole maintain an average valencein a range of from 4.5 to 5.5. Preferably, the octahedral elements inthe octahedral sheet as a whole maintain an average valence of 4 and thetetrahedral elements in the tetrahedral sheet as a whole maintain anaverage valence of 5.

The octahedra comprises six elements, such as oxygen, placed around andbonded by covalent bond to the aforementioned octahedral element. Bysharing corner atoms, the octahedra bond with each other to form anoctahedral sheet. The tetrahedra, on the other hand, comprises threeelements, such as oxygen, and carbon provided from an organic portion,placed around and bonded by covalent bond to the aforementionedtetrahedral element. These nearest neighbor elements are bonded to thetetrahedral element by covalent bond to form a tetrahedron. Thetetrahedra bond with each other to form a tetrahedral sheet. Theoctahedra and the tetrahedra form a layered structure by sharing thecorner elements such as oxygen. The layer is formed in this manner. Inboth of the octahedra and the tetrahedra, the corner elementsdistributed around the octahedral site and the tetrahedral site may beany element capable of forming a covalent bond with the elements locatedat the octahedral site and the tetrahedral site of the octahedra and thetetrahedra. Specifically mentioned as the corner element include oxygen.

The layer comprising a layered structure of a tetrahedral sheet and anoctahedral sheet preferably has a zirconium phosphate structure as shownin FIG. 1.

Referring to FIG. 1, a zirconium phosphate structure comprises anoctahedron containing, for instance, zirconium atom as the element forthe octahedral site, and six atoms of an element such as oxygen whichsurround the octahedral element. The surrounding elements are bonded tothe octahedral element by covalent bond. The structure also comprises atetrahedron containing, for instance, phosphorus atom as the element forthe tetrahedral site, and four atoms of an element such as oxygen whichsurround the octahedral element. The surrounding elements are bonded tothe tetrahedral element by covalent bond. By sharing the cornerelements, the octahedra and the tetrahedra separately form an octahedralsheet and a tetrahedral sheet, respectively. An octahedron is bonded toa tetrahedron by sharing the side plane of the octahedron with the basalplane of the tetrahedron. In other words, three corner elements, e.g.,oxygen atoms, of the octahedron also function as the three cornerelements (oxygen atoms) of the tetrahedron to bond the octahedron to thetetrahedron. In a zirconium phosphate structure, two tetrahedral sheetsare bonded to both sides of a single octahedral sheet. Furthermore,carbon atom (C) of the organic portion is located at the oxygen site onthe outer side of the tetrahedron (the corner oxygen which is not sharedwith an octahedron). Thus, the organic portion is bonded by covalentbond to the tetrahedral element.

The layer having the zirconium phosphate structure can be expressed by amolecular formula of Me[XO₃.R]₂, where Me represents at least oneelement selected from the group consisting of titanium (Ti), zirconium(Zr), germanium (Ge), tin (Sn), lead (Pb), and cerium (Ce); X representsat least one selected from the group consisting of phosphorus (P) andarsenic (As); and R represents an organic portion; provided that theelement expressed by X is bonded by covalent bond to the organic portionrepresented by R.

A layer of a zirconium phosphate structure can be obtained even when atrivalent aluminum (Al) or a tetravalent silicon (Si) is used in theplace of the pentavalent element, such as phosphorus (P), for thetetrahedral element. However, in case of using an element other than apentavalent element, particularly a tetravalent element well known in aclay mineral, the surrounding four oxygen ions must each supply a4/4-valent, i.e., a monovalent electron on the average. In such a case,each of the oxygen must also supply a 2/2-valent, i.e., a monovalentelectron to bond to the neighbor silicon or to form an ionic bond withthe octahedron. Thus, an Si--O--Si bond is also formed to result in astructure represented by a clay mineral as illustrated in FIG. 2.Accordingly, a zirconium phosphate structure cannot be obtained.

In case a pentavalent element such as phosphorus is provided as theelement for the tetrahedral site of the tetrahedron, the tetrahedralelement forms a covalent bond with the apical oxygen atom pointedoutward by attracting a monovalent electron therefrom, while receiving4/3-valent electrons each from the other three oxygen atoms. Each of thethree oxygen atoms remains with 2/3 valence (2-4/3=2/3). This results insuch a structure comprising a tetrahedral element surrounded by six2/3-valent anions. Thus, the average valence of the octahedral elementfor the entire octahedral sheet must be tetravalent (2/3×6=4). Thediscussion above is based on the well-known so-called Pauling's rulewhich describes the coordination of inorganic crystals. A structureaccording to Pauling's rule can be implemented by providing anoctahedral element with a valence of from 3.5 to 4.5 and a tetrahedralelement with a valence of from 4.5 to 5.5.

The octahedral element is preferably at least one selected from theGroup consisting of titanium (Ti), zirconium (Zr), Germanium (Ge), tin(Sn), lead (Pb), and cerium (Ce). Particularly preferred is to select atleast one element from the Group consisting of Zr, Ti, and Ce. Thetetrahedral element is at least one selected from the group consistingof phosphorus and arsenic. The structure thus obtained is relativelystable; furthermore, the starting materials therefore are also stable,and are readily and industrially available.

A layer comprising two tetrahedral sheets each bonded to each side of anoctahedral sheet is known in the art. However, no layered zirconiumphosphate comprising one each of the sheets above in a manner similar tothat of a clay mineral, kaolinite is known, nor a synthetic product ofthis type is reported to the present. In view of Pauling's rule, theoxygen atoms constituting the octahedra must have a valence of 2/3.Thus, if only one tetrahedral sheet were to be bonded to one side of theoctahedral sheet, the total oxygen valence will be insufficient toprovide a kaolinite-like structure.

According to the hybrid material of the present invention, the averagevalence of the octahedral element for the octahedra over the entireoctahedral sheet is in a range of from 3.5 to 4.5, and the averagevalence of the tetrahedral element for the tetrahedra over the entiretetrahedral sheet is in a range of from 4.5 to 5.5. However, theoctahedral site or the tetrahedral site may be vacant. In such a case,the octahedral site or the tetrahedral site is regarded as having avalence of zero.

In addition to the defects represented by vacancies above, the layer maycontain line defects attributed to the loss of regular ordering incrystals, or a glassy structure comprising a partially amorphousportion.

In a zirconium phosphate structure, however, the ideal structure aboveremains the same even if an organic portion (R) were to be bondedthereto, and without incorporating a defect described above.Accordingly, it is possible to obtain a defect-free layer composed ofcontinuously bonded single crystals over a length of several millimetersor even longer. Furthermore, because organic portions are bondedpreviously to the layer, a composite using coarse crystals can bereadily formed therefrom and a polymer.

It is also possible to introduce organic portions into a zirconiumphosphate structure without inducing defects in the crystal structure.Moreover, a perfect and coarse crystal can be obtained free of problemssuch as consuming much time. Thus, organic portions can be regularly anddensely arranged along the host, i.e., the layer. Accordingly, even ifthe content of the organic polymer should be increased, the polymer canstill reflect the structure of the host, i.e., the layer. By takingadvantage of these characteristics, the water resistance of a polyamide,or the heat resistance as well as the weathering resistance inherent inmost of the thermoplastic polymers can be exhibited effectively by thecomposite.

The desired hybrid material can be obtained by forming a layercomprising continuous structural unit of at least about 10 Å, and theresulting hybrid material can be used as a catalyst. A common zirconiumphosphate of a type as shown in FIG. 3 inevitably involves acrystallization step effected by means of a hydrothermal reaction andthe like. Thus, the resulting zirconium phosphate is obtained with acontinuous structural unit of 100 Å or longer. On the other hand, theorganic derivative of zirconium phosphate constituting the layeraccording to the present invention aims to develop a layered structurefrom the synthetic step at room temperature by taking advantage of theinteraction between the organic portions. Accordingly, a layercomprising minimum structural units 10 Å in length can be combined intoa continuous structure capable of forming a composite.

In the hybrid material according to the present invention, the organicportion expressed by R may be of any kind, so long as it contains acarbon (C) atom which can be directly bonded to the inorganic element(X) located at the tetrahedral site of the tetrahedra. That is, anyorganic molecule can be used irrespective of it being a monomer or apolymer.

More specifically, organic portions suitable for use above as R includean aliphatic hydrocarbon group, an alicyclic hydrocarbon group, anaromatic hydrocarbon group, an organic portion having a halogen such asfluorine or chlorine bonded thereto; a characteristic group containingan oxygen such as a hydroxyl group or an oxy group; a complex group suchas an ether group, a carboxylic acid, an ester group, an acyl group, anacetonyl group, or an anisoyl group; a characteristic group containingsulfur such as a methylthio group; a characteristic group containing onenitrogen atom such as a methylamino group; a characteristic groupcontaining two or more nitrogen atoms such as a phenylazo group; and aheterocyclic group. In the process according to the present invention,one group or a combination of two or more organic portions can be used.

If an organic portion having an unsaturated group such as a vinyl groupor an acrylic group is used among the organic portions above, a hybridmaterial comprising a bridged polymer or a copolymer with an olefin(e.g., ethylene, propylene, butadiene, isoprene, and isobutylene), avinyl compound (e.g., styrene, vinyl chloride, and vinyl acetate), or anacrylic compound (e.g., methyl methacrylate) can be obtained by bringingthe organic portion into contact with the polymerizable compoundsenumerated above.

A second organic portion may be further bonded to the functional groupthereof. The second organic portion may be a polymer or a monomer.

In case the organic portion is an amine or a carboxylate group, theorganic portion can be polymerized with a lactam, a diamine, or adicarboxylic acid to form an amido bond.

A lactam is selected from the group consisting of butylolactam,pivalolactam, caprolactam, caprylolactam, enantholactam, undecanolactam,and dodecanolactam. One or a combination of two or more selected fromthe group may be used.

A diamine may be selected from the group consisting of an aliphaticchain diamine such as trimethylenediamine, tetramethylenediamine,pentamthylenediamine, hexamethylenediamine, octamethylenediamine,decamethylenediamine, dodecamethylenediamine, 2,2,4- or2,4,4-trimethylhexamethylenediamine; an aromatic diamine such asphenylenediamine or xylylenediamine; or an alicyclic diamine. One or acombination of two or more selected therefrom can be used.

Usable dicarboxylic acid is selected from an aliphatic chaindicarboxylic acid such as adipic acid, pimelic acid, glutamic acid,suberic acid, octadecanoic diacid, or sebacic acid; an aromaticdicarboxylic acid such as terephthalic acid and or isophthalic acid; oran alicyclic dicarboxylic acid. One or a combination of two or moreselected therefrom can be used.

From the viewpoint of availability of the material, price, etc., andamong the materials above, caprolactam or dodecalactam is preferred as alactam; hexamethylenediamine or tetramethylenediamine is preferred as adiamine; and adipic acid or sebacic acid is preferred as a dicarboxylicacid.

Thus, a hybrid material comprising a polyamide resin containing unitlayers of zirconium phosphate based layered substance bonded to thematrix by covalent bond can be obtained by heating a polymerizablematerial selected from those above together with a catalyst such as anamine or a carboxylic acid, or with a layered zirconium phosphate basedcompound having an amino group or a carboxylic group bonded thereto.

By using ethylene glycol and the like as a polymerization initiator incase the organic portion described above has an ester group, the organicportion can be polymerized with a lactone such as caprolactone by anester bond. Furthermore, in case the organic portion is an epoxy group,a phenolic group, etc., the organic portion may be bonded to an epoxyresin or phenolic resin by incorporating an amine, a formamide, etc.

As described above, a polymer can be bonded to the functional groupbelonging to an organic portion of the hybrid material according to thepresent invention. Furthermore, the organic portion itself may be apolymer. The both ends of the polymer thus bonded may be further bondedto the inorganic layer, or only one end thereof may be bonded to thelayer. An active group may remain in the polymer. Otherwise, aconstitution as such in which the polymer chains are bridged by thelayer may be employed.

In case the both ends of the polymer are bonded to the layer (i.e., incase one end of the polymer is bonded to a first layer and the other endis bonded to another layer neighboring to the first layer), the polymerchains densely arrange between the unit layers. Furthermore, in such acase, because no active groups remain therein, a hybrid material havingexcellent stability and a certain degree of rigidity can be obtained,yet free from embrittlement.

In case only one end is bonded to the layer, the polymer molecular chaincan move relatively freely. Thus, a hybrid material imparted withexcellent moldability can be obtained.

In case the polymer results with a bridged morphology, a molding can bereadily obtained with a hybrid material containing less quantity of anorganic molecule. Thus, a hybrid material having excellent propertiesconcerning heat resistance and hardness can be obtained.

In the hybrid material according to the present invention, thecharacteristics inherent in the organic portion intercalated between thelayers are more clearly exhibited with increasing distance between thelayers. From this point of view, an average interlayer spacing ispreferably 4.4 nm or more. By setting the interlayer spacing in a rangeof 4.4 nm or more, the organic portion intercalated between the layerscan freely exhibit the favorable characteristics concerning, e.g.,tensile strength and moldability. More preferably, an average interlayerspacing is 5.0 nm or more.

The basal spacing between the layers can be increased by increasing themolecular weight of the organic portion bonded by covalent bond to thetetrahedral element of the tetrahedra constituting the layer, or byincreasing the number of carbon atoms in the straight chain.

The hybrid material according to the present invention can be used as anultraviolet (UV) radiation absorber by properly selecting the elementconstituting the inorganic component. For instance, by using titanium orcerium as the octahedral element for the octahedral sheet constitutingthe layer, a UV-absorbing function can be imparted to the resultinghybrid material. Furthermore, the hybrid material according to thepresent invention is usable as a coating material for resins and woodmaterials (surface hardening agent) by taking advantage of the inherentcharacteristics concerning heat resistance and hardness. The hybridmaterial according to the present invention is also applicable toautomobile parts or to machine parts by making the best of excellentrigidity and toughness thereof when used as a molding. It is alsopossible to use the hybrid material as a wrapping material by utilizingthe barrier function on gas permeation, and, since the material is heatresistant, in addition, it can be used as an IC packaging resin and thelike in the fabrication of electronic components. Furthermore, anoptical or an electromagnetic element such as a light-emitting elementor an electric conductor can be implemented by further intercalating anarray of organic portions having electrons in excess, e.g., phenylgroups and vinyl groups. By taking such a constitution, theelectron-rich organic portions or the organic portions having additionalelectrons incorporated therein by adding metallic ions or halogenmolecules are allowed to react with each other. It is also possible toimpart an optical or an electromagnetic function to the hybrid materialby controlling the type of the metal used in the layer or the alignmentof the organic portions. The hybrid material according to the presentinvention may be combined with fibrous materials such as glass fibers orsepiolite, platy materials such as micas and talc, or other types ofmaterials such as silica gel.

In the of using a zirconium phosphate-type layer as the layer of thehybrid material of the present invention, the organic to be bonded tothe tetrahedral element of the tetrahedra may be selected not only fromthe organic portions capable of forming a direct bond with an organicpolymer, but also from the groups having a function as an initiator forradical polymerization (e.g., a peroxide, an azo group, a disulfidegroup, a metallic carbonyl group, or a metallic phenyl complex), a groupwhich functions as an initiator for anion polymerization such as ametallic alkyl group, a group which functions as an initiator for cationpolymerization, a polymerization initiator such as an amino group or acarboxyl group which initiates condensation polymerization of nylon andthe like, or a polymerization inhibitor or retarder such as a diphenylor a nitrophneyl or a nitro group. Thus, the structure and theproperties of the hybrid material can be controlled in various ways.

In case an aromatic group such as a phenyl group or a naphthyl group isbonded to the tetrahedral group of the tetrahedra, it has been foundthat the aromatic rings align themselves densely and approximately inparallel with each other due to the restriction posed by the size of theorganic portion. By doping a transition metal element such as Fe, Ni,Co, Ti, Zr, or Hf to the hybrid material of such a structure, a hybridmaterial which functions as an electron donor can be obtained. As aresult, a material which exhibits an optical function, i.e., a noveltype of light-emitting function, can be obtained. The electron donorthus obtained also functions as an initiator for anion polymerization.More specifically, accordingly, it can be used as an initiator for theanion polymerization of polyolefins such as polypropylene, as well as oflactams.

The process for producing a hybrid material according to a second aspectof the present invention comprises reacting a substance containing anoctahedral element for the octahedra constituting an octahedral sheetwith a substance containing the elements constituting the octahedraexcept for the element at the octahedral site, and also with a substancecontaining a tetrahedral element for the tetrahedra constituting atetrahedral sheet and an organic portion bonded by covalent bond to thetetrahedral element, in such a manner that the valence of the octahedralelements averaged over the entire octahedral sheet may fall in a rangeof from 3.5 to 4.5, and that the valence of the tetrahedral elementsaveraged over the entire tetrahedral sheet may fall in a range of from4.5 to 5.5.

That is, a hybrid material according to the first aspect of the presentinvention can be implemented by a process which simply comprisesreacting three types of substances.

More specifically, the process for producing a hybrid material accordingto the present invention comprises reacting a substance containing anoctahedral element expressed by "Me" for the octahedra constituting theoctahedral sheet, with a substance containing the elements constitutingthe octahedra except for the element expressed by Me, and also with asubstance containing a tetrahedral element expressed by "X" for thetetrahedra constituting the tetrahedral sheet and an organic portionbonded by covalent bond to the element expressed by X, in such a mannerthat the average valence of the Me over the entire octahedral sheet mayfall in a range of from 3.5 to 4.5, and that the average valence of theX over the entire tetrahedral sheet may fall in a range of from 4.5 to5.5. In this manner, the octahedra can be bonded to make an octahedralsheet, and the tetrahedra make a tetrahedral sheet. The both sheets forma layered structure (layer). Because the tetrahedral element X and theorganic portion are bonded to each other by covalent bond, the layerthus generated retains the covalent bond between X and the organicportion.

In case a hybrid material comprising a zirconium phosphate-type layerexpressed by Me[XO₃.R]₂, where Me represents at least one elementselected from the group consisting of titanium, zirconium, germanium,tin, lead, and cerium; X represents at least one selected from the groupconsisting of phosphorus and arsenic; and R represents an organicportion is produced, and in case the element expressed by X is bonded bycovalent bond to the organic portion represented by R, the hybridmaterial is formed according to the reaction described below.

By reacting the substance containing the tetrahedral element expressedby X and an organic portion expressed by R bonded by covalent bond tothe element X with a substance containing the octahedral elementexpressed by Me and with a substance containing an element other thanMe, e.g., an oxygen, a zirconium phosphate structure is synthesizedaccording to the following reaction scheme:

    2R--PO(OH).sub.2 +MeOX.sub.2 →Me(R--PO.sub.3).sub.2 +2HX+2H.sub.2 O(1)

    2R--POX'.sub.2 +MeOX.sub.2 +3H.sub.2 O→Me(R--PO.sub.3).sub.2 +2HX+4HX'                                                 (2)

    2R--PO(OH).sub.2 +MeX.sub.4 →Me(R--PO.sub.3).sub.2 +4HX(3)

    2R--PO(OR').sub.2 +MeOX.sub.2 +3H.sub.2 O→Me(R--PO.sub.3).sub.2 +2HX+2R'OH                                                (4)

where, X and X' each represent a halogen ion; and OR' represents analkoxide. In general, a zirconium phosphate compound is producedaccording to a reaction expressed by:

    2H.sub.2 PO.sub.3 +ZrOCl.sub.2 →Zr(HPO.sub.3).sub.2 +2HCl(5)

and only H⁺ ions align on the surface of the layer. Accordingly, theresulting zirconium phosphate hardly undergoes an instantaneouscrystallization. However, in an organic derivative of zirconiumphosphate, organic portion expressed by R align on the surface of thelayer, and also densely. Because the formation of a layered alignment isaccelerated by the Van der Waals' interaction or the hydrogen bond amongthe organic portion represented by R, it is assumed that a layeredstructure is realized even in the reaction at room temperature.

A compound having a zirconium phosphate structure is generallysynthesized by reacting phosphoric acid with a halide of a metal (Me)for the octahedral site (expressed by MeX_(m), where X represents ahalogen atom such as Cl, Br, and I; and m is generally an integer of 4)or an acid halide (expressed by MeOX_(n), where n is generally aninteger of 2). By using an acid oxyhydrate expressed by R--PO(OH)₂, or ametal salt thereof (expressed by R--PO(OMe)₂, where Me representssodium, potassium, etc.), or an acid halide expressed by R--POX₂ in theplace of phosphoric acid in the reaction above, an organic derivative ofthe zirconium phosphate containing a directly bonded organic portion canbe obtained.

More specifically, usable phosphorus compounds include an aromaticphosphorus compound such as phenylphosphonic acid, aminobenzylphosphonicacid, or naphthylphosphate; a straight chain aliphatic phosphonic acidsuch as methylphosphonic acid, ethylphosphonic acid, or propylphosphonicacid; a branched aliphatic phosphonic acid such as t-butylphosphonicacid; a phosphonic acid containing an amino group, such asaminomethylphosphonic acid, amino ether phosphonic acid,aminoethylphosphonic acid, or aminopropylphosphonic acid; a compoundhaving a carboxylic group, such as 2-carboxylphosphoric acid orphosphonium acetic acid; an alkali metal salt of carbonyl, such as asodium salt of phosphonium acid; an amino acid having an amino group anda carbonyl group, such as aminophosphonium propionic acid oraminophosphonic butyric acid; a p-alkoxide or a halide having anunsaturated bond, such as dimethylvinylphosphoric acid orallylphosphoric chloride; a phosphonic acid having a phosphate group,such as methylenediphosphonic acid; a phosphorus alkoxide containingsulfur on carbon, such as diethylmethylthiomethylphosphonate; aphosphorus alkoxide containing pyrrole, such asdiethylpyrrolinomethylphosphonate;

an alkoxide containing an oxoalkyl, such asdimethyloxopropylphosphonate; a phosphorus alkoxide having an alkoxideon the terminal thereof, such as trimethylphosphonoacetic acid andethyldimethylphosphonoacetic acid; a phosphorus alkoxide having crotonicacid or an ester, such as triethylphosphoric crotonate; a sodium salt ofa phosphonic acid containing sulfur and an amino group, such asmonosodium S-aminoethylthiophosphate; and a phosphate containing asaccharide bonded thereto, such as sodium ribosephosphate and sodiumα-D-glucosephosphate. At least one compound selected from thoseenumerated above is used.

Thus, a solution of the phosphorus compound above is mixed at roomtemperature with (a) a substance containing a halide of an element (Me)for the octahedral site of the octahedra (e.g., a zirconium oxychloride,zirconium tetrachloride, titanium tetrachloride, or germaniumtetrachloride) or an aqueous solution thereof; an aqueous solution of,e.g., cerium sulfate or cerium hydroxide; or an alkoxide such astitanium isopropoxide; and (b) a substance containing an element (e.g.,oxygen) constituting the octahedra other than Me, in such a manner thatphosphorus (P) or arsenic (As) is incorporated at a quantity twice aslarge as that of the octahedral element. A layered substance or aprecursor thereof can be obtained as a precipitate. The concentration ofthe aqueous solutions or the alcoholic solutions containing thecompounds above is not particularly restricted, but preferably, thesolution contains P or As at a concentration of from 0.05 to 10M, andmore preferably, from 0.1 to 2M. Similarly, the concentration of thesolution containing the octahedral element such as zirconium ispreferably controlled in a range of from 0.005 to 1M, and morepreferably, in a range of from 0.01 to 0.05M.

In the reaction above, a crystallization treatment is preferablyeffected after synthesizing the hybrid material at room temperature. Thecrystallization treatment can be effected by, for instance, performinghydrothermal treatment in a sealed vessel in a temperature range of from100° to 250° C., and by using HF as a catalyst, heating the resultingproduct at a temperature range of from 40° to 80° C. under reflux. It isnot preferred to perform the treatment at a temperature of 250° C. orhigher, not only because it requires an equipment resistant to a highpressure corresponding to the equilibrium water vapor pressure of 40atoms or higher, but also because of the possibility of causingmodification of the bonding organic portions.

Although depending on the type of the starting material, the startingmaterials in the process according to the present invention are reactedby heating the materials in a temperature range of from 10° to 200° C.,more preferably, in a range of from 20° to 90° C. Furthermore, thesubstance containing the octahedral element and that containing theelements for the octahedra other than the octahedral element need not bethe same. However, a single substance containing both of the octahedralelement and the elements for the octahedra other than the octahedralelement may be used as well.

Among the organic derivatives of zirconium phosphate type thussynthesized as the hybrid materials, the compound containing the organicportion having a functional group capable of forming a bond with anorganic polymer is further mixed with an organic monomer, and subjectedto a conventional polymerization reaction to obtain a hybrid materialcomprising an organic polymer bonded to the organic portion.

In case polyamide is used for the organic polymer above, a hybridmaterial containing polyamide can be obtained from a mixture of lactamand a compound having a carboxyl group or an amine group used as thestarting material for the synthesis. The resulting mixture is sealed ina tube and heated to obtain the hybrid material. Specifically mentionedas the usable lactam include butylolactam, pivalolactam, caprolactam,caprylolactam, enantholactam, undecanolactam, and dodecanolactam. One ora combination of two or more selected from the group may be used.

To the mixture is added the zirconium phosphate type compound, and acatalyst, such as aminohexanoic acid, is added for polymerizing lactam.The desired hybrid material can be obtained by heating the resultingmixture in a polymerization tube at a temperature 270° C. or lower for aduration of from 1 to 24 hours.

A nylon salt can be formed at room temperature as an intercalatedcompound by reacting a first compound having a carboxyl group or anamino group in water with a diamine or a dicarbonyl compound having thesame valence as that of the number of organic portions of the firstcompound. By further mixing a nylon salt produced though a reaction ofan equivalent diamine or dicarbonyl compound with the resulting hybridmaterial, a nylon salt containing a zirconium phosphate type compoundcan be obtained. Thus, the two-step operation described above can beeffected simultaneously to obtain a nylon salt containing a zirconiumphosphate type compound. More specifically, the process above can beeffected at room temperature by mixing and stirring a mixture ofdicarboxylic acid and a zirconium phosphate type compound having acarbonyl group, to which a diamine containing amino groups equivalent tothe number of carbonyl groups of the dicarboxylic acid is added.Otherwise, the same can be effected at room temperature on a mixture ofdiamine and a zirconium phosphate type compound having an amino group,to which dicarbonyl groups equivalent to the number of carbonyl groupsof the amino groups are added. It is also possible to mix anamino-containing zirconium phosphate compound with a compound containingcarbonyl groups. A hybrid material of polyamide can be obtained byheating the resulting nylon salt in a vessel equipped with anitrogen-inlet pipe and a depressurizing cock at a temperature in arange of from 200° to 300° C. while flowing gaseous nitrogen or underreduced pressure.

A hybrid material containing polypropylene can be obtained by subjectingan organic portion containing an unsaturated bond, such as an allylgroup, to a polymerization reaction with propylene in the presence of acatalyst such as titanium chloride. Other usable catalysts in thepolymerization reaction include titanium tetrachloride on a magnesiumchloride carrier or titanium trichloride on a magnesium chloridecarrier. The hybrid material can be obtained in the see polymerizationreaction commonly employed for producing a polyolefin.

It is also possible to previously mix a polymerizable monomer for acommon organic polymer with a zirconium phosphate type compound having agroup capable of forming a bond therewith to produce a composite withthe polymer. Such additional polymers include a polymer containing acarbon-carbon bond for the principal chain (e.g., polystyrene, polyvinylacetate, polybutadiene, or polyacetylene), a polymer containing oxygenin the principal chain thereof (e.g., polyether, polyacetal, polyester,or polycarbonate), a nitrogen-containing polymer (e.g., polyamine,polypeptide, polyurethane, polyimide, polyimidazole, polyoxazole,polypyrrole, or polyaniline), a sulfur-containing polymer (e.g.,polysulfide or polysulfone), a phosphorus-containing polymer (e.g.,polyphosphoric acid or polyphosphine), a condensation bridged polymer(e.g., a phenolic resin, a urea resin, a melamine resin, an epoxy resin,or an alkyd resin), or an addition-bridged polymer (e.g., a vinyl esterresin or an unsaturated polyester).

The method for controlling the content of an organic component and aninorganic component in a hybrid material according to a third aspect ofthe present invention comprises:

in producing a hybrid material by reacting a substance containing anoctahedral element for the octahedra constituting an octahedral sheetwith a substance containing the elements constituting the octahedraexcept for the element at the octahedral site, and also with a substancecontaining a tetrahedral element for the tetrahedra constituting atetrahedral sheet and an organic portion bonded by covalent bond to thetetrahedral element, provided that the average valence of the octahedralelements over the entire octahedral sheet fall in a range of from 3.5 to4.5, and that the average valence of the tetrahedral elements over theentire tetrahedral sheet fall in a range of from 4.5 to 5.5;

adding at a predetermined quantity ratio to the substance containing theelement for the tetrahedral site and the organic group bonded thereto bycovalent bond, the substance containing the element for the tetrahedralsite but to which no organic portion is bonded.

Considering the process for producing a hybrid material according to thesecond aspect of the present invention, a part of the tetrahedraconstituting the hybrid material can be left over with their tetrahedralelements (X) non-bonded to the organic portions. This can be achieved byadding, at a predetermined ratio, a substance having no organic portionbonded thereto to a substance containing the tetrahedral element and theorganic portions bonded to the tetrahedral element. Thus, by controllingthe quantity of the addition of the substance having no organic portionsbonded thereto, it is possible to control the ratio of the organicportions, i.e., the content ratio of the organic component and theinorganic component.

By thus controlling the quantity of the organic component in a hybridmaterial, for instance, the density of bonds between an inorganiccomponent and a polymer can be changed. Accordingly, the alignment ofthe polymer molecular chains as well as the bridged density among themolecules can be modified. Thus, the conflicting characteristics of ahybrid material, for instance, the mechanical properties such as therigidity, toughness, heat resistance, or hardness, and the moldability,can be controlled relatively freely.

In the process according to the present invention, a substancecontaining an element for the tetrahedral site of the tetrahedra buthaving no organic portion bonded thereto is added at a predeterminedquantity to a starting material which comprises an element for thetetrahedral site of the tetrahedra and an organic portion bonded theretoby covalent bond. In this manner, a hybrid material partially comprisingtetrahedra having no organic portion bonded thereto can be obtained.Thus, by controlling the quantity of addition of the substance above,the content of the organic portions, i.e., the content of organiccomponent in the hybrid material can be controlled.

Zirconium phosphate is generally synthesized by using phosphoric acid.In contrast to a general case, the process according to the presentinvention comprises reacting a compound of zirconium and the like withan organic phosphonic acid or an organic phosphoric acid having anorganic portion bonded thereto. For instance, by performing synthesis ina manner similar to the above using an inorganic phosphoric acid and theorganic phosphoric acid above in an aqueous solution, or in a mixedsolution previously prepared using an alcohol, a layer comprisinguniformly dispersed therein tetrahedra having hydroxyl groups bonded tothe tetrahedral elements (X) and organic portions (R) bonded to X.

In case of obtaining an organic derivative of zirconium phosphate or aclay mineral by means of an ordinary ion exchange treatment, it isassumed possible to control the organic content by lowering the ionexchange ratio or by mixing ions. However, the size of the intercalatedions changes by the ion exchange treatment. As a result, in case of areaction in which the interlayer spacing changes, the reaction tends toproceed concentrated on the reaction-initiated layer. Accordingly,unlike the method according to the present invention, it is difficult touniformly disperse the organic portion over the entire layer by using anordinary process.

Similar to zirconium phosphate of an ordinary type, the inorganic ions(e.g., H⁺ in case of a hydroxyl group) bonded to the syntheticallyobtained X can be exchanged with another inorganic or organic cation byion exchange treatment.

When organic portions account for approximately 100%, the organicportions align extremely densely on the surface of the layer. Moreover,because bonding occurs at a high ratio, improvements on mechanicalproperties such as rigidity and hardness as well as the coloring effectattributed to the alignment of the organic portions can be readilyobserved. When organic portions account for about 30%, hydrophobiceffect as well as a reinforcing effect well comparable to those of anorganic derivative of a clay mineral obtained by ion exchange treatmentcan be realized. In case of a rigid hybrid material having a phenylgroup and the like in the organic portion thereof and which containsfrom 10 to 50% of organic portions, the interlayer region becomes moresparse to be expected to exhibit an adsorption effect. However, if thecontent of the organic portions becomes as low as 3% or even lower, thehybrid material is no longer a characteristic material, and is foundalmost the same as a common layered inorganic compound.

The bonding strength of the organic portion to the polymer can be variedby mixing the types of organic portions above. Accordingly, thealignment of the polymer molecule chains as well as the bridging densityamong the molecules can be controlled. Thus, the conflictingcharacteristics of a hybrid material, for instance, the mechanicalproperties such as the rigidity, toughness, heat resistance, orhardness, and the moldability, can be controlled relatively freely. Itis also possible in the present method to determine the average size ofthe organic portion in such a manner that the organic portions may alignwith a proper density on the surface of the layer. The alignment of theorganic portions on the surface of the layer and the relative structureof the organic portions with respect to the layer (more specifically,whether the organic portions are aligned in parallel with the layer orperpendicular to the layer) can be controlled in this manner. As aresult, the characteristics of the hybrid material can be controlled bycontrolling the higher order structure of the polymer bonded to theorganic portion or the electronic interaction between the organicportion and the added ions.

In case of producing a hybrid material comprising a zirconium phosphatetype layer expressed by Me[XO₃.R]₂ (where Me represents at least oneelement selected from the group consisting of titanium, zirconium,germanium, tin, lead, and cerium; X represents at least one selectedfrom the group consisting of phosphorus and arsenic; and R represents anorganic portion; provided that the element expressed by X is bonded bycovalent bond to the organic portion represented by R) by reacting asubstance containing Me (where Me represents at least one elementselected from the group consisting of titanium, zirconium, germanium,tin, lead, and cerium) with a substance containing oxygen as well as asubstance containing X (which represents at least one selected from thegroup consisting of phosphorus and arsenic) and an R (an organicportion) bonded by covalent bond to X, a substance containing Xnon-bonded with R is added at a predetermined quantity ratio to asubstance containing X and R bonded by covalent bond to X.

The method for controlling the content of an organic component and aninorganic component in a hybrid material according to a third aspect ofthe present invention comprises:

in producing a hybrid material by reacting a substance containing anoctahedral element for the octahedra constituting an octahedral sheetand a substance containing the elements constituting the octahedraexcept for the element at the octahedral site, with a substancecontaining a tetrahedral element for the tetrahedra constituting atetrahedral sheet and a first organic portion bonded by covalent bond tothe tetrahedral element, provided that the average valence of theoctahedral elements over the entire octahedral sheet fall in a range offrom 3.5 to 4.5, and that the average valence of the tetrahedralelements over the entire tetrahedral sheet fall in a range of from 4.5to 5.5;

controlling the number of functional groups of the first organicportion, said functional group being capable of bonding with a secondorganic portion; and bonding the second organic portion to thefunctional group of said first organic portion.

In the process for producing a hybrid material according to the secondaspect of the present invention, the present method may further comprisecontrolling the number of functional groups capable of bonding to asecond organic portion and bonding the second organic portion to thefunctional group of the first organic portion. In this manner, moresecond organic portion are bonded to the first organic portion having alarger number of functional groups. Thus, by controlling the number ofthe functional groups, the quantity of bonded second organic portion canalso be controlled. Thus, the content of organic and inorganic componentcan be controlled.

As described above, the conflicting characteristics of a hybridmaterial, for instance, the mechanical properties such as the rigidity,toughness, heat resistance, or hardness, and the moldability, can becontrolled relatively freely as described in the third aspect of thepresent invention by controlling the quantity of the organic componentin the hybrid material.

The method according to the present invention comprises controlling thenumber of functional groups (capable of bonding to a second organicportion) of a first organic portion in a substance containing an elementfor the tetrahedral site of tetrahedra and the first organic portionbonded by covalent bond to said element. If, for instance, the number ofthe functional groups be zero, no second organic portion can be bondedto the particular organic portion. Reversely, the number of the secondorganic portion can be further increased by increasing the number of theaforementioned functional groups. Thus, the content of the organicportions, i.e., the content of organic component in the hybrid materialcan be controlled according to a manner described above.

An organic portion capable of bonding by covalent bond to thetetrahedral element of a tetrahedra include a group (A) capable offurther bonding to another compound or a polymer, such as a carbonylgroup, an amino group, a group having an unsaturated carbon bond, anepoxy group, a phenolic group, an alkoxide group, an aminocarboxylicgroup, a sulfonate group, and a saccharide; and a group (B) which is notcapable of further extending the bond by an ordinary reaction, such as astraight chain aliphatic group, a phenyl group, a branched aliphaticgroup, and an alcohol. After mixing the both in a manner described abovein the process according to the second aspect of the present invention,the resulting mixture is reacted with a compound containing zirconium,titanium, etc., to obtain a layer to which the organic portions areuniformly bonded.

The technique according to the present invention enables, for the firsttime, uniformly dispersing organic portions differing from each other inthe molecular size. The present invention uses no ion exchangetreatment. A technique for uniformly dispersing an inorganic substancein an organic polymer has been conventionally employed, and is effectivefor improving mechanical properties such as rigidity and heatresistance. Thus, in case the organic portions capable of bonding to anorganic polymer of group (B) above account for 100%, an effect as ahybrid material can be obtained. In case the organic portions of group(B) account for 0%, a highly stable material comprising polymers allbonded to X elements on the surface of the layer can be obtained. Themoldability, such as the plasticity, of the hybrid material increaseswith increasing content of the organic portions belonging to group (B),whereas superior properties, e.g., rigidity and heat resistance, areobtained with increasing content of the organic portions belonging togroup (A).

An improvement on mechanical properties such as rigidity and hardness, acoloring function, a water-repelling effect, a reinforcing effect, or anadsorption function, can be obtained by controlling the content of theorganic component. Furthermore, by varying the content of the organicportions capable of bonding to a polymer, the density of bonding with apolymer can be changed. Thus, in the same manner as in the third aspectof the present invention, the alignment of polymer molecular chains aswell as the bridging density among the molecules can be controlled.

In case of producing a hybrid material comprising a zirconium phosphatetype layer expressed by Me[XO₃.R]₂ (where Me represents at least oneelement selected from the group consisting of titanium, zirconium,germanium, tin, lead, and cerium; X represents at least one selectedfrom the group consisting of phosphorus and arsenic; and R represents anorganic portion; provided that the element expressed by X is bonded bycovalent bond to theorganic portion represented by R) by reacting asubstance containing Me (where Me represents at least one elementselected from the group consisting of titanium, zirconium, germanium,tin, lead, and cerium) with a substance containing oxygen, as well as asubstance containing X (which represents at least one selected from thegroup consisting of phosphorus and arsenic) and an R (an organicportion) bonded by covalent bond to X, the number of functional groupscapable of bonding to the second organic portions of R above iscontrolled.

The present invention is described in further detail by making referenceto specific Examples below. In the examples described below, the term"basal spacing" signifies an average distance between two neighboringlayers in case of regarding a layer of a zirconium phosphate typestructure as one layer.

EXAMPLE 1

While stirring using a magnetic stirrer, a 1,000-ml portion of a 0.02Maqueous solution of zirconium oxychloride was added dropwise at roomtemperature into 50 ml of 0.8M aqueous solution of 2-carboxylphosphoricacid. The precipitate obtained through the reaction was filtrated andrinsed repeatedly until the pH value of the filtrate became 7. Theresulting precipitate was subjected to vacuum drying at 30° C. for aduration of 10 hours. The powder thus obtained was investigated by meansof X-ray diffraction using Cu-Kα radiation on system RAD-B (manufacturedby Rigaku Corp.). FIG. 4 gives the X-ray diffraction pattern a for theproduct thus obtained. The X-ray diffractogram a yields a patternsimilar to that of a substance having a zirconium phosphate structure,with a principal diffraction peak marked A. The diffractogram reads thata layered substance having a zirconium phosphate structure with a basalspacing of 1.6 nm is obtained. Infrared (IR) absorption spectrumobtained by IR absorption analysis is given in FIG. 5. The spectrummarked with a indicates that the product has a carboxyl group and aphosphate group. Considering that a substance (2-carboxylphosphoricacid) having both carboxyl group and phosphate group bonded by covalentbond is used as the starting material, it is confirmed that a compoundof a zirconium phosphate type with 2-carboxylic acid bonded thereto bycovalent bond is obtained. By taking the basal spacing obtained from theX-ray diffractogram marked with a in FIG. 4 and the presence of a COOHgroup indicated in the spectrum a of FIG. 5 into consideration,2-carboxylic acid molecules are found to be aligned regularly on thesurface of a unit layer in a manner shown schematically in FIG. 6.

A 2-g portion of the thus obtained powder product was mixed with 2-, 3-,or 4-g portion of ε-caprolactam in a mortar, and the resulting powdermixture was charged into a Pyrex glass tube. After drying the powdermixture inside the glass tube at 40° C. for a duration of 5 hours, theglass tube was sealed airtight. The glass tube with the powder mixturesealed therein was placed inside an oven maintained at a temperature of260° C. to effect polymerization reaction for a duration of 10 hours.The reaction product was then taken out of the glass tube, and the lowmolecular product was removed by treating the product in a boiling waterfor a duration of 10 minutes. The resulting product was dried in vacuumat 80° C. for a duration of 24 hours. The basal spacing of the hybridmaterials thus obtained were determined by means of X-ray diffraction,and the quantity ratio of the organic components to the inorganiccomponents (organic/inorganic) were obtained by means ofthermogravimetric analysis (TG). The results obtained by X-raydiffraction are given in FIG. 7. The basal spacings for each of theproducts were determined from peaks marked with A, B, and C, and isgiven in Table 1. The curves obtained by TG are shown in FIGS. 8 to 11,and are marked with a. The quantity ratio (organic/inorganic) wasobtained by combusting the hybrid material at a temperature in a rangeof from 200° to 500° C., and the measured weight loss (the quantity ofthe organic matter removed by combustion) is given as a curve markedwith a. Thus, the quantity ratio is calculated by taking the casecontaining 0% of 6-nylon as a standard (see FIG. 8). The results aregiven in Table 1 as 6-nylon content.

                  TABLE 1                                                         ______________________________________                                                             Quantity of 6-nylon                                                                        Basal spacing                               FIG. 7 Curves in TG results                                                                        (% by weight)                                                                              (nm)                                        ______________________________________                                        c      FIG. 9        50           3.9                                         b      FIG. 10       60           5.0                                         a      FIG. 11       62           6.5                                         ______________________________________                                    

Based on the results obtained by IR analysis, an amido bond was found togenerate on the resulting product (see FIG. 5, curve b). The absorptionbands marked with amido I, amido II, and amido III in the IR spectrum ofFIG. 5 are assigned to polyamide. These absorption bands indicate thatthe hybrid material thus obtained contains an intercalated 6-nylon, andthat the 6-nylon molecular chains are bonded approximately perpendicularto the inorganic layers.

EXAMPLE 2

Zirconium phosphate containing 2-carboxylate groups bonded thereto wassynthesized in the same manner as in Example 1, and a 10 g portionthereof was mixed with 100 ml of ion-exchanged water. The resultingmixture was charged into a 200-ml volume Teflon autoclave, and wassubjected to crystallization by effecting hydrothermal treatment at 200°C. for a duration of 10 days. The crystallized product was then takenout of the autoclave, and was dried at 80° C. for 10 hours afterfiltration. The powder thus obtained as a product was identified byX-ray diffraction. The result is given as diffractogram marked with b inFIG. 4. The X-ray diffraction pattern yields a peak B, and is similar tothat of a substance having a zirconium phosphate structure. Thus, theproduct is identified as a crystallized compound having a zirconiumphosphate structure with a basal spacing of 1.3 nm.

A 1.2-g portion of the thus obtained powder product was mixed with 22 gof ε-caprolactam and 1.8 g of aminohexanoic acid, and the resultingmixture was subjected to polymerization in the see manner as thatdescribed in Example 1 to synthesize a hybrid material. After removingthe low molecular substance from the hybrid material in a manner similarto that described in Example 1, the hybrid material was dried, and wassubjected to tensile tests following JIS K7113 standard. The results aregiven in Table 2.

                  TABLE 2                                                         ______________________________________                                                   Tensile strength                                                                         Tensile elastic modulus                                            (MPa)      (GPa)                                                   ______________________________________                                        Example 2    110          2.3                                                 Comparative Example 1                                                                      85           1.5                                                 Comparative Example 2                                                                      98           1.9                                                 Comparative Example 3                                                                      70           1.1                                                 ______________________________________                                    

COMPARATIVE EXAMPLE 1

A 2-g portion of α-zirconiumphosphate was suspended in 1 liter of water,and after adding 2.16 g of 12-aminododecanoic acid therein, stirring ofthe resulting mixture was effected at 55° C. for 2 hours. The productthus obtained was filtrated, rinsed, and dried in vacuum at 50° C. for aduration of 16 hours. An organic derivative of zirconium phosphate wasobtained from the resulting product according to the ion-exchangeprocess disclosed in JP-A-Hei5-306370. The organic derivative ofzirconium phosphate thus obtained was then subjected to polymerizationand molding in the same manner as in Example 1 to perform the tensiletest as described in Example 2. The results are given in Table 2 above.

COMPARATIVE EXAMPLE 2

A 10-g portion of montmorillonite from Yamagata prefecture was immersedinto 150 ml of 1M aqueous aminocaproic acid solution whose pH wascontrolled to 5.2 by using hydrochloric acid, and ion-exchange treatmentwas effected at room temperature for a duration of 2 hours. After theresulting product was rinsed, filtrated, and dried, a hybrid materialwith 6-nylon was obtained in the same manner as described in Example 1.The hybrid material thus obtained was then subjected to tensile test ina manner similar to that described in Example 2. The results are givenin Table 2 above.

COMPARATIVE EXAMPLE 3

After mixing 22.5 g of ε-caprolactam with 2.5 g of 6-aminohexanoic acidin mortar, the resulting mixture was sealed in a glass tube to effectthe polymerization reaction in the same manner as in Example 1 to obtaina polyamide resin. Tensile test was performed on the resulting resin inthe same manner as that described in Example 2. The results are given inTable 2.

Table 2 clearly reads that the hybrid material obtained in Example 2yields higher tensile strength and elastic modulus as compared withthose obtained on the products obtained in Comparative Examples 1 to 3.

EXAMPLE 3

2-Carboxylphosphoric acid and phenylphosphonic acid were mixed at aratio by molar [(2-carboxylphosphoric acid)/(2-carboxylphosphoricacid+phenylphosphonic acid)] of 1, 0.7, 0.5, 0.3, or 0, and a 0.8Maqueous solution was each prepared by using the resulting mixtures. Eachof the resulting aqueous solutions was reacted with zirconiumoxychloride in the same manner as described in Example 1 to obtain eacha solid precipitate. The solid precipitates thus obtained were eachrinsed, filtrated, and dried. Each of the products thus obtained wasstudied by X-ray diffraction to give the diffractograms marked with a asshown in FIG. 4 and in FIGS. 12 to 15. Thus, the curves in FIG. 4, FIG.12, FIG. 13, FIG. 14, and FIG. 15 are for the samples each obtained at aratio by molar [(2-carboxylphosphoric acid)/(2-carboxylphosphoricacid+phenylphosphonic acid)] of 1, 0.7, 0.5, 0.3, and 0, respectively.In each of the figures, the curve marked with a yields a pattern similarto that of a substance having a zirconium phosphate structure, and apeak A corresponding to the basal spacing. Thus, it was confirmedtherefrom that the products are each a layered substance having azirconium phosphate structure. Then, the products were each crystallizedin the same manner as that described in Example 2, and the resultingproducts were each identified by X-ray diffraction. The results obtainedon the crystallized products are given as diffractograms marked with bas shown in FIG. 4 and in FIGS. 12 to 15. In each of the figures, thecurve marked with b yields a pattern similar to that of a substancehaving a zirconium phosphate structure, and a peak B corresponding tothe basal spacing. Thus, it was confirmed therefrom that the productsare each a layered substance having a zirconium phosphate structure. Thebasal spacing for each of the products is given in Table 3. From theresults obtained by X-ray diffraction (curves a and b in FIG. 4 andFIGS. 12 to 15), carbonyl groups and phenyl groups were found to remainat the initial mixing ratio, and to be uniformly dispersed in the finalproduct thus obtained. More specifically, this was concluded from thechange in basal spacing with changing the content ratio of the carbonyland phenyl groups. That is, in case phenyl groups account for 50% ormore, the basal spacing depends only on the phenyl groups that arelarger in size than the carbonyl groups. The 2-carbonyl groups fill theinterstices of the phenyl groups, and 2-carbonyl groups were found topose no influence on the basal spacing.

Among the zirconiumphosphate obtained above, those having a ratio bymolar [(2-carboxylphosphoric acid)/(2-carboxylphosphoricacid+phenylphosphonic acid)] of 1.0, 0.7, or 0.5 was mixed (2.0 g) with2.0 g of ε-caprolactam, followed by polymerization and rinsing. Theproducts thus obtained were each studied by X-ray diffraction. Theresults are given in FIG. 16. The ratio by molar [(2-carboxylphosphoricacid)/(2-carboxylphosphoric acid+phenylphosphonic acid)] is shown by Xand is given in the figure. The basal spacing for each of the productswas determined from the peak A, B, or C. The results are given in Table3.

                  TABLE 3                                                         ______________________________________                                                  Basal Spacing (nm)                                                              Before adding                                                     Molar ratio*                                                                              6-nylon    After adding 6-nylon                                   ______________________________________                                        1.0         1.29       3.9                                                    0.7         1.46       4.4                                                    0.5         1.55       4.4                                                    0.3         1.55       --                                                     0           1.55       --                                                     ______________________________________                                         *Ratio by molar: [(2carboxylphosphoric acid)/(2carboxyl-phosphoric acid +     phenylphosphonic acid)]-                                                 

It can be seen from the foregoing that the basal spacing slightlyincreases with increasing content of phenyl groups, however, the X-raydiffraction peak assigned to the basal reflection becomes considerablybroad. The presence of a phenyl group induces disordering in the layerstacking, and impairs the regular structure of the intercalatedpolymers.

EXAMPLE 4

A 1,000-ml portion of 0.02M aqueous titanium tetrachloride solution wasmixed with 50 ml of 0.8M aqueous solution of aminopropylsulfonic acid toobtain a precipitate. The resulting precipitate was subjected tofiltration, rinsing, and drying in the same manner as described inExample 1, which was followed by crystallization by means ofhydrothermal reaction and drying. Ten grams of the resulting titaniumphosphate having an aminopropyl group bonded thereto was suspended in500 ml of water. After adding 80 ml of 1M aqueous adipic acid solutioninto the suspension, 40 ml of 1M aqueous hexamethylenediamine solutionwas further added therein. The resulting mixed solution was heated at40° C. for a duration of 1 hour. After filtration and adding 100 ml ofwater, the resulting product was placed in a 200-ml volume Teflon vesseland was sealed airtight therein. The treatment was performed at 120° C.for a duration of 10 hours. The resulting product was filtered, and wasdried in vacuum at 40° C. for a duration of 48 hours. The product thusobtained was subjected to IR analysis. The result is given as a spectrummarked with a in FIG. 17. The generation of --COO⁻ and NH₃ ⁺ radicalswere confirmed on the IR spectrum thus obtained. Thus, the formation ofan intercalated nylon salt was confirmed. The resulting product wascharged into a reaction tube equipped with an inlet for gaseousnitrogen, and was treated at 280° C. for a duration of 30 minutes. Aminobond was confirmed to generate on the product thus obtained (see FIG.17, IR absorption spectrum b). Thus, a hybrid material of titaniumphosphate containing 6,6-nylon with amino group bonded thereto wasobtained.

EXAMPLE 5

An aqueous solution was prepared by dissolving 62 g of2-carboxylphosphoric acid [(COOH)(CH₂)₂ PO(OH)₂ ] in 500 ml ofion-exchanged water. Another aqueous solution prepared by dissolving 65g of zirconium oxychloride octahydrate (ZrCl₂.O.8H₂ O) in 10 l of waterwas added dropwise over about 30 minutes into the aqueous solution abovewhile stirring. A solid matter was found to generate, but was dispersedin the aqueous solution. The suspension thus obtained was subjected torepeated filtration using a filter press and rinsing with 10 l of wateruntil the pH of the filtrate became 6.5. One litter of water was addedto the wet cake thus obtained, and the resulting product was chargedinto a steel autoclave to perform hydrothermal treatment for a durationof 3 days. The product was freeze-dried thereafter to obtain a2-carboxyl derivative of zirconium phosphate in the form of a powder.

A 100-g portion of the powder thus obtained was mixed with each of 120-,160-, and 400-g portion of ε-caprolactam, and the resulting mixtureswere each heated at 100° C. for a duration of 30 minutes. After purginga glass vessel with argon, the resulting mixtures were each sealedairtight therein to perform heat treatment at 250° C. for a duration of6 hours. The products thus obtained were each coarsely ground in analumina mortar, and were each immersed in 5 l of water at 80° C. for aduration of 1 hour. The products were each subjected to filtration, andthe filtrate was dried in vacuum at 80° C. for a duration of 24 hours.

The hybrid materials thus obtained were each molded in the same manneras in Examples 1 and 2, and were subjected to X-ray diffraction and tothe evaluation of mechanical properties. The results are given in Table4.

                  TABLE 4                                                         ______________________________________                                                          Sample No.                                                                    1     2        3                                            ______________________________________                                        Addition of ε-caprolactam to 100 g of Zr                                                  120     160      400                                      phosphate derivative (g)                                                      Elastic modulus (at 23° C.) (GPa)                                                          3       2.5       2                                       Tensile strength (at 23° C.) (MPa)                                                         5       95       100                                      Charpy impact strength (kJ/m.sup.2)                                                               0.5     9         10                                      Thermal Deformation Temperature                                                                   --      230      200                                      (under a stress of 1.82 MPa)                                                  Basal spacing (nm)  4.1     5.0      >10                                      Average number of intercalated carbon                                                             19      31       >60                                      atoms calculated from basal spacing                                           ______________________________________                                    

The thermal deformation temperature for sample No. 1 was not availablebecause it underwent melting during the measurement. However, theelastic modulus for sample No. 1 was good.

Table 4 reads that a hybrid material having a basal spacing of 5.0 nm orlonger exhibit excellent tensile strength and thermal deformationproperties.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

What is claimed is:
 1. A hybrid material comprising:a layer containingan octahedral sheet comprising octahedra linked with each other toprovide a sheet structure and a tetrahedral sheet comprising tetrahedralinked with each other to provide a sheet structure, said tetrahedralsheet being linked to said octahedral sheet by plane to plane; and afirst organic portion bonded by covalent bond to an element located atthe tetrahedral site of the tetrahedra, each of said octahedra having anelement at the octahedral site thereof with a valence in the range offrom 3.5 to 4.5 on average over the entire octahedral sheet, and each ofsaid tetrahedra having an element at the tetrahedral site thereof with avalence in the range of from 4.5 to 5.5 on average over the entiretetrahedral sheet.
 2. A hybrid material as claimed in claim 1, whereinthe layer is a zirconium phosphate layer expressed by Me[XO₃.R]₂, whereMe represents at least one element selected from the group consisting oftitanium, zirconium, germanium, tin, lead, and cerium; X represents atleast one selected from the group consisting of phosphorus and arsenic;and R represents said first organic portion, said X being bonded bycovalent bond to said R.
 3. A hybrid material as claimed in claim 1,wherein said first organic portion is a polyamido- orpolypropylene-group.
 4. A hybrid material as claimed in claim 1, whereinsaid first organic portion has a functional group and a second organicportion bonded to said first organic portion through said functionalgroup.
 5. A hybrid material as claimed in claim 1, wherein the layer hasa basal spacing of 4.4 nm or more on average from adjacent layers.
 6. Ahybrid material as claimed in claim 5, wherein the layer has a basalspacing of 5.0 nm to 100 nm on average from adjacent layers.
 7. Aprocess for producing a hybrid material comprising the step of:reactinga substance containing: an element which functions as an element at theoctahedral site of octahedra constituting an octahedral sheet; and otherelements constituting the octahedral sheet except for the element at theoctahedral site, with a substance containing: an element at thetetrahedral site of tetrahedra constituting a tetrahedral sheet; a firstorganic portion that is combined by covalent bond with the element atthe tetrahedral site; and other elements constituting the tetrahedralsheet except for the element at the tetrahedral site, in such a mannerthat the resulting octahedral sheet has elements at the octahedral sitesthereof with an average valence in the range of from 3.5 to 4.5 and thatthe resulting tetrahedral sheet has elements at the tetrahedral sitesthereof with an average valence in the range of from 4.5 to 5.5, therebyobtaining a hybrid material having a layer containing the octahedralsheet comprising octahedra linked with each other to provide a sheetstructure and the tetrahedral sheet comprising tetrahedra linked witheach other to provide a sheet structure, said tetrahedral sheet beinglinked to said octahedral sheet by plane to plane, and a first organicportion bonded by covalent bond to the element located at thetetrahedral site of the tetrahedra.
 8. A process for producing a hybridmaterial as claimed in claim 7, wherein the reaction step is performedby reacting a substance containing: at least one element selected fromthe group consisting of titanium, zirconium, germanium, tin, lead, andcerium; and oxygen, with a substance containing: at least one elementselected from the group consisting of phosphorus and arsenic; the firstorganic portion bonded thereto; and oxygen, to obtain a zirconiumphosphate layer expressed by Me[XO₃.R]₂ for said layer, where Merepresents at least one element selected from the group consisting oftitanium, zirconium, germanium, tin, lead, and cerium; X represents atleast one selected from the group consisting of phosphorus and arsenic;and R represents the first organic portion, said X being bonded bycovalent bond to said R.
 9. A process for producing a hybrid material asclaimed in claim 7, further comprising the step of:controlling thecontent of an organic component and an inorganic component in a hybridmaterial, by adding a substance containing the element for thetetrahedral site but to which no organic portion is bonded to thesubstance containing the element for the tetrahedral site at apredetermined quantity ratio and the organic portion bonded thereto bycovalent bond.
 10. A process for producing a hybrid material as claimedin claim 8, further comprising the step of:controlling the content of anorganic component and an inorganic component in the hybrid material byadding a substance containing the X which is not bonded with the R to asubstance containing the X and the R bonded to the X at a predeterminedquantity ratio.
 11. A process for producing a hybrid material as claimedin claim 7, wherein the first organic portion has a functional group,further comprising the step of:controlling the content of an organiccomponent and an inorganic component in the hybrid material bycontrolling the gross number of functional group of the first organicportion which is capable of bonding with a second organic portion; andbonding the second organic portion to the functional group of said firstorganic portion.
 12. A process for producing a hybrid material asclaimed in claim 8, wherein the first organic portion has a functionalgroup, further comprising the step of:controlling the content of anorganic component and an inorganic component in the hybrid material bycontrolling the gross number of the functional group of the firstorganic portion which is capable of bonding to a second organic portion;and bonding the second organic portion to the functional group of saidfirst organic portion.
 13. A surface hardening material comprising:alayer containing an octahedral sheet comprising octahedra linked witheach other to provide a sheet structure and a tetrahedral sheetcomprising tetrahedra linked with each other to provide a sheetstructure, said tetrahedral sheet being linked to said octahedral sheetby plane to plane; and an organic portion bonded by covalent bond to anelement located at the tetrahedral site of the tetrahedra; saidoctahedral sheet comprising octahedra each having an element at theoctahedral site thereof with a valence in the range of from 3.5 to 4.5on average over the entire octahedral sheet, and said tetrahedral sheetcomprising tetrahedra each having an element at the tetrahedral sitethereof with a valence in the range of from 4.5 to 5.5 on average overthe entire tetrahedral sheet.
 14. A wrapping material comprising:a layercontaining an octahedral sheet comprising octahedra linked with eachother to provide a sheet structure and a tetrahedral sheet comprisingtetrahedra linked with each other to provide a sheet structure, saidtetrahedral sheet being linked to said octahedral sheet by plane toplane, and an organic portion bonded by covalent bond to an elementlocated at the tetrahedral site of the tetrahedra; said octahedral sheetcomprising octahedra each having an element at the octahedral sitethereof with a valence in the range of from 3.5 to 4.5 on average overthe entire octahedral sheet, and said tetrahedral sheet comprisingtetrahedra each having an element at the tetrahedral site thereof with avalence in the range of from 4.5 to 5.5 on average over the entiretetrahedral sheet.
 15. An ultraviolet radiation absorber comprising:alayer containing an octahedral sheet comprising octahedra linked witheach other to provide a sheet structure and a tetrahedral sheetcomprising tetrahedra linked with each other to provide a sheetstructure, said tetrahedral sheet being linked to said octahedral sheetby plane to plane; and an organic portion bonded by covalent bond to anelement located at the tetrahedral site of the tetrahedra; saidoctahedral sheet comprising octahedra each having titanium or cerium atthe octahedral site thereof, and said tetrahedral sheet comprisingtetrahedra each having an element at the tetrahedral site thereof with avalence in the range of from 4.5 to 5.5 on average over the entiretetrahedral sheet.
 16. An electron donor comprising:a layer containingan octahedral sheet comprising octahedra linked with each other toprovide a sheet structure and a tetrahedral sheet comprising tetrahedralinked with each other to provide a sheet structure, said tetrahedralsheet being linked to said octahedral sheet by plane to plane; and anaromatic organic group bonded by covalent bond to the element located atthe tetrahedral site of the tetrahedra; said octahedral sheet comprisingoctahedra each having an element at the octahedral site thereof with avalence in the range of from 3.5 to 4.5 on average over the entireoctahedral sheet, said tetrahedral sheet comprising tetrahedra eachhaving an element at the tetrahedral site thereof with a valence in therange of from 4.5 to 5.5 on average over the entire tetrahedral sheet,and said layer being doped with transition metal ions.
 17. An electrondonor as claimed in claim 16, wherein the electron donor is an anionpolymerization initiator.